Boiler-flue joint.



L. W. CRAFT.

BOILER FLUE JOINT.

APPLICATION FILED APR.3| 1915.

Patented Dec. M, 1915.

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W1 Uwagfb war ens a nnwrs w. onar'r, or cnrcaoo, ILLINOIS, as'srornon or onn-nanr 'ro JAMES GUZDIEREY,

' or onrcaeo, rnrirnors.

BUILElt-FILUE 301N1 9.

Specification of Letters Patent.

Application filed April it, 1915. Serial No. 19,007.

To all whom itmag concern y Be it known that l, lLnwrs W. CRAFT, a citizen of the' United States, residing at Ghicago, in the county of @001; and State of llllinois, have invented new and useful llm rovements in Boiler-Flue Joints, of which the following is a specification.

This invention relates to boiler flue joints, and it has for its object to efiectlmprovements in the art of connecting a boiler due with the line sheet.

Heretofore it has been found difllcult to produce a thoroughly leak-proof flue joint owing to the expansion and contraction caused by variations-in temperature. The present. invention-has for its object to produce a construction whereby absolute contact between the flue sheet and the flue Will be maintained at all times irrespective of the degree-oi temperature.

A further object of the invention is to produce a leak-proof flue joint which will e simple in construction, which will not involve the use of auxiliary ferrules or thim'bles and which willbe efi'ective in operation.

With these and other ends. in View which will readily appear as the nature of the invention is better understood, the same consists in the improved construction and novel arrangement and combination of parts which will be hereinafter fully described and particularly pointed out in the claims.

In the accompanying drawing has been illustrated a simple and preferred form of the invention, it being, however, understood that no limitation is, necessarily made to the precise structural details therein ex hibited, but that changes, alterations and modifications within the scope of the claims may be resorted to when desired.

' In the drawing, Figure 1 is a sectional view showing a portion of a due sheet and a flue projected therethrough. Fig. 2 is a similar view showing the flue forcedto its seat. Fig. 3 is a similar view showing the appearance after-the line has been expanded. Fig. i is a similar vie'w showing the appearance after the formationof the inner bead.

Corresponding parts in the several figures I 16 surrounding and concentric with said opening. The inner and outer side walls 17, 18 of the groove 16 are straight and parallel, as clearly seen in Fig. 1.

The flue 19 which is to be fitted in the opening 15 is provided at its outer end with an annular l ip or flange 20 which is turned back to a position parallel with the body of the flue or with the axis thereof. This lip, Which may be conveniently formed by the use of proper tools, is spaced from the body of the fine a distance equal to the distance between the groove 16 and the open ing 15,'so that said lip by forcing the outer end of the fine in the direction of the flue sheet will enter the groove 16 and completely till the latter, suitable pressure be ing applied in any well known manner to properly assemble the parts. The assembled position is shown in Fig. 2. After the flue has been assembled with the sheet, the outer end thereof is expanded with the result that the material lying between the opening 15 and the groove 16 is forced or tiltedoutward, together with the portion of thelip 20 that lies within the groove, said portion being tilted outward in the direction of the outer Wall 18 of the groove. The portion 21 of the material of the flue sheet lying between the opening 15 and the groove 16 will thus cooperate with the. lip 20 to form a beveled joint whereby the parts will be very intimately assembled. This construction is particularly indicated in 3. The parts having been assembled in the manner described, ll next form on the flue, adjacent to the inner face'of the flue sheet, an annular bead 22,: indicated inFig. 4 of the drawings, said bead being upset against the nular groove with parallel side walls surrounding the flue-opening. By the subsequent expansion of the flue, the material of the flue as well as that of the flue sheet is tilted in the directionof the outer side walls of the groove, thereby forming a lock joint that prevents the outward displacement of the flue, said lock joint being reinforced by the formationof the head 22 which also cooperates with the flue sheet to form a tight ]01I1t.

When expansion takes place due to in crease in temperature, the diameter of the opening 15 is decreased, while the diameter of the due is increased, and the partsare thus intimately wedged together. When contraction takes place due to reduction of temperature, the tendency will "be for the diameter of the opening 15 to become enlarged, while the diameter of the line hecomes redueed. ,Under these Circumstances it is obvious that with the construction customa-rilv resorted to leakage is liable to take place. Under my improved construction as herein shown and described, when contraction takes place, due to reduction of tem perature, that portion of the flue sheet indicated at 21 which lies between the opening '15 and the groove 16 will expand against the back-turned lip 20 of the flue, the diameter of which is lessened, thus preserving a perfectly tight joint, the loosening or disassem-- blage of the parts being prevented, partly due to the fact that by expanding the outer end of the'flue, the parts are tilted to form I an inclined lock ioint and partly owing to the presence of the internal bead 22.

Having thus described the invention, what .is claimed as new, is I 1. A flue sheet having a flue opening and an annular groove surrounding the same, and a flue having a back-turned lip engaging said groove, said fine being expanded,

the material lving between the inner wall of the groove and the outer wall of the line being tilted in an outward direction because of said expansion.

2. A flue sheethaving a flue opening and an annular groove surrounding the same,

and a flue having a back-turned lip engaging said groove, said line being expanded, the material lying between the inner wall of the groove and the outer wall of the flue being tilted in an outward direction because of said expansion, and said flue being provided with an annular head adjacent to the inner face of the flue sheet.

3. The improvement in the art of assembling a flue with a flue sheet which consists in providing the flue sheet with an annular groove surrounding the line opening there- I in, said groove having parallel walls; form ing on the outer end of the flue a backturned lip lying parallel. to the axis of the I LEWIS W. CRAFT.

Witnesses: I Winnmn J. Cnoann, WM. Coon. 

